Adapter device for image capturing device

ABSTRACT

A network camera system is configured such that an adapter is connected with a digital camera, and the adapter is connected with a network to which a client is also connected. A video signal representing a real-time image and a digital image signal representing a high-resolution still image are transmitted from the camera to the adapter. The adapter has a function of a file server and allows the client to download image data corresponding to the high-resolution still image. The adapter device further has a function of a streaming server and transmits streaming data representing the real-time image. The client can transmit an operation command to the adapter through the network, and the adapter can transfer the command to the camera to perform the operation required by the client.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of co-pending U.S. patentapplication Ser. No. 10/385,470, filed Mar. 12, 2003, which claimspriority of Japanese Patent Application No. 2002-068434, filed Mar. 13,2002. The disclosure of each of these documents is expresslyincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

The present invention relates to an adapter device which is connected toimage capturing devices such as video cameras and transmits capturedimages to image browsing terminals at distant places through a networksuch as the Internet.

Recently, the broadband Internet such as ADSL or CATV system has becomeavailable at a relatively low cost, and an Internet server such as HTTPserver and/or FTP server can be used as a home-use server.

Besides the HTTP server and/or the FTP server, a streaming server whichtransmits a real-time video image captured by a video camera or the likeis now available. The streaming server is expected to be used for homesecurity systems. Therefore, such a personal streaming server may bewidespread as the broadband becomes popular.

In the meantime, recently, a digital camera provided with a CCD havingseveral millions of image pixels has been developed and used. If such adigital camera and the streaming server are used in combination, aninexpensive network camera system having a high performance may beexpected.

However, the size of the data output by such a digital camera may beapproximately 1 Mega bytes even if the data is compressed. In order totransmit such data, even if the broadband transmission line is used, onethrough several seconds may be required to transmit one image. Dependingon a condition of the communication line, more transmission time may berequired. Therefore, even if such a digital camera is used to configurethe network camera system, it is difficult to use the digital camera totransmit the high-resolution real-time image to a distant place.

SUMMARY OF THE INVENTION

The present invention is advantageous in that an adapter is provided,with which an image captured by an image capturer such as a digitalcamera can be transmitted through a network to another computerconnected to the network.

According to an aspect of the invention there is provided a networkcamera system including at least one client, a digital camera and anadapter, the client and the adapter being connected with each otherthrough a network.

In such a system, the camera is provided with an image capturer, ananalog video signal outputter that outputs an analog video signalrepresenting a moving image captured by the image capturer, a digitalimage signal outputter that outputs a digital image signal representinga still image captured by the image capturer, a control commandreceiver, and an operation controller that controls an operation of thecamera in accordance with the control command received through thecontrol command receiver.

Further, the adapter is provided with a file server that receives thedigital image signal from the camera and stores an image filerepresenting the still image captured by the image capturer, the fileserver allowing the at least one client to download the image file fromthe file server through the network, a streaming server that receivesthe analog video signal from the camera and creates streaming datacorresponding to the received video signal, the streaming data beingtransmitted to the client through the network, an adapter commandreceiver that receives an operation command from the client through thenetwork, and an adapter command transmitter that transmits a controlcommand corresponding to the operation command to the camera.

Furthermore, the client is provided with a browser that downloads theimage file from the file server and displays an image represented by theimage file, the browser being capable of processing the streaming dataand displaying the moving image represented by the streaming data, and aclient command transmitter that allows an operator to input an operationcommand indicative of an operation to be executed by the camera andtransmits the operation command to the adapter through the network.

As above, according to one aspect, the network camera system isconfigured such that an adapter is connected with a digital camera, andthe adapter is connected with a network to which a client is alsoconnected. A video signal representing a real-time image and a digitalimage signal representing a high-resolution still image are transmittedfrom the camera to the adapter. The adapter has a function of a fileserver and allows the client to download image data corresponding to thehigh-resolution still image. The adapter further has a function of astreaming server and transmits streaming data representing the real-timeimage. The client can transmit an operation command to the adapterthrough the network, and the adapter transfer the command to the camerato perform the operation required by the client.

Optionally, the operation to be executed by the camera may includecapturing a still image when the operation command is input to theclient command transmitter by the operator.

Further optionally, the digital image signal representing the capturedimage output by the digital image signal outputter is received by thefile server and stored in the adapter.

In a particular case, the operation to be executed by the camera mayinclude at least one of zooming operation of the camera, capturing astill image and adjustment of brightness of an image captured by thecamera.

Still optionally, a resolution of the still image may be greater thanthat of the moving image.

According to another aspect of the invention, there is provided anadapter for a network camera system. The network camera system mayinclude at least one client, a digital camera and the adapter, and theclient and the adapter are connected with each other through a network.The camera is capable of outputting an analog video signal representinga moving image and digital image signal representing a still imagecaptured by the camera, an operation of the camera being controllable byinputting a control command to the camera. The client may include abrowser that downloads the image file from a file server and displays animage represented by the image file, the browser being capable ofprocessing streaming data and displaying a moving image represented bythe streaming data. The client may further include a command transmitterthat allows an operator to input an operation command indicative of anoperation to be executed by the camera and transmits the operationcommand to the adapter through the network. In such a network, theadapter is provide with a file server that receives the digital imagesignal from the camera and stores an image file representing the stillimage captured by the camera, the file server allowing the at least oneclient to download the image file through the network, and a streamingserver that receives the analog video signal from the camera and createsstreaming data corresponding to the received video signal, the streamingdata being transmitted to the client through the network. The adapter isfurther provided with a command receiver that receives an operationcommand from the client through the network, and a command transmitterthat transmits a control command corresponding to the operation commandto the camera.

According to a further aspect of the invention, there is provided anadapter capable of being connected with an image capturer andtransmitting a captured image to a terminal connected to a networksystem as digital image data. The adapter is provided with a firstinterface receiving an analog signal output by the image capturer, asecond interface capable of transmitting/receiving digital data to/fromthe image capturer, a first image data generator that generates firstdigital data based on the analog signal received through the firstinterface, a network interface that exchanges data with the terminalthrough the network, and a controller that controls the first interface,the second interface, the first image data generator and the networkinterface.

Optionally, the analog signal may be an analog video signal.

Further optionally, the network may include the Internet.

Still optionally, the adapter may be configured to transmit data to theterminal in accordance with the HTTP.

Further optionally, the adapter may further include a casing. The firstinterface and the second interface may be formed on the casing, and theadapter may be configured such that, by securing the casing onto theimage capturer, an analog signal output terminal of the image captureris connected to the first interface and a digital signal output terminalof the image capturer is connected to the second interface.

With such a configuration, no cables are necessary for connecting thecamera and the adapter, and handling thereof can be facilitated.

In a particular case, the adapter includes a fixation mechanism thatsecurely fixes the adapter to the image capturer.

Optionally, the fixation mechanism may include a positioning member thatis used to adjust a positional relationship of the adapter with respectto the image capturer when the adapter is secured to the image capturer.

Further optionally, the positioning member may include at least twoguide pins which are inserted in corresponding holes formed on the imagecapturer.

Optionally, the fixation mechanism may include locking claws whichengage with engageable portions formed on the image capturer.

In this case, the fixation mechanism may further include a releasemechanism which is operated to release engagement of the locking clawswith the engageable portions.

According to another aspect of the invention, there is provided anadapter to be connected with an image capturer. The adapter is providedwith a first terminal and a second terminal which are connectable withthe image capturer, a third terminal connectable to a communicationnetwork, a controller capable of controlling the image capturer, animage processer that processes an image signal to generate first digitalimage data, and a server that manages digital image data including thefirst digital image data.

With this structure, the first terminal receives a video signal of amoving image, the image processer generating the first digital imagedata by processing the video signal. A control signal instructing theimage capturer to capture second digital image data representing animage having a higher resolution than an image represented by the firstdigital image data is transmitted from the controller through the secondterminal. The second digital image signal, which is generated inresponse to the control signal transmitted to the image capturer throughthe second terminal, is received through the second terminal. Further,another control signal requesting for capturing of the second digitalimage data by the image capturer is transmitted from a computerconnected to the communication network to the controller through thethird terminal. The server transmits one of the first digital image dataand the second digital image data to the computer through the thirdterminal.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 shows an entire configuration of a network camera systemaccording to a first embodiment;

FIG. 2 is a block diagram of a digital camera of the network camerasystem;

FIG. 3 is a block diagram of an adapter device of the network camerasystem;

FIG. 4 is a flowchart illustrating an operation of the digital camerashown in FIG. 2;

FIG. 5 is a flowchart illustrating an operation of the adapter device;

FIG. 6 is an exemplary screen shot when an “Image Browsing/CameraControlling Program” is executed in a client PC;

FIG. 7 is an exemplary screen shot when an “Image Browsing/CameraControlling Program” is executed in a client PC;

FIG. 8 is a flowchart illustrating an operation of the client PC; and

FIG. 9 is a perspective view of a digital camera and an adapter deviceaccording to a second embodiment.

DESCRIPTION OF THE EMBODIMENT

Hereinafter, an embodiment of the invention will be described withreference to the accompanying drawings.

FIG. 1 schematically shows an entire configuration of a network camerasystem according to a first embodiment of the invention. The networkcamera system 1 includes a digital camera 110, an adapter device 200, anADSL modem 301 and a client PC 400.

The digital camera 110 is capable of capturing a high-resolution digitalstill image, a maximum size of which is 3200×2400 (pixels). Further, thedigital camera 110 has a video output function, and is capable ofoutputting a video signal output by the CCD of the digital camera 110 asan NTSC signal. The digital camera 110 also has a USB (Universal SerialBus) interface as a communication interface to communicate with anexternal device.

The digital camera 110 is connected with the adapter device 200 througha USB (Universal Serial Bus) cable 102 and a video cable 103. Theadapter device 200 receives the NTSC signal representing an moving imagethrough the video cable 103, and the high-resolution digital still imagethrough the USB cable 102, from the digital camera 110. Further, theadapter device 200 is capable of controlling the digital camera 110 bysending control commands through the USB cable 102.

The adapter device 200 has both the USB interface and the Ethernet(trademark) interface, which will be described later. The adapter device200 is connected to the Internet through a router type ADSL modem 301and an Ethernet cable 302. The adapter device 200 has a file serverfunction, and capable of storing the high-resolution digital stillimages received from the digital camera 110 in a storage unit thereof ashigh-resolution digital still image files, and allows the thus storedimage files to be downloaded by another computer connected to theInternet.

The adapter device 200 is capable of encoding each frame of the analogmoving images into a low-resolution (e.g., VGA size: 640×480) digitalimage data. Further, the adapter device 200 has a streaming serverfunction, and is capable of transmitting the encoded low-resolutiondigital image data to another computer connected to the Internet. Itshould be noted that the adapter device 200 according to the firstembodiment is capable of encoding and transmitting the image on asubstantially real-time basis. Accordingly, another computer connectedto the Internet is capable of communicating at a sufficientcommunication speed, the low-resolution digital image data captured bythe digital camera 110 and encoded by the adapter device 200 can bebrowsed as a real-time moving image.

The client PC 400 has a main body 401, a monitor 402, an input device403 including the keyboard, mouse and the like, and the ADSL modem 404.

The client PC 400 can be connected to the Internet through the ADSLmodem 404, and receive the low-resolution digital image data encoded bythe adapter device 200. By subsequently display the images thusreceived, the images captured by the digital camera 110 can be displayedon the monitor 402 as a moving image substantially simultaneously withthe capturing thereof. Further, the client PC 400 is capable ofdownloading the high-resolution digital still image data stored in thestorage unit of the adaptor device 200, and displaying the imagerepresented by the downloaded data.

FIG. 2 shows a block diagram of the digital camera 110 according to thefirst embodiment. The digital camera 110 includes a controller 111, avideo interface 112, an image capture optical system 113, a CCD (ChargeCoupled Device) module 114, an image capture control unit 115, a storage116, a communication I/O (input/output module) 117, a USB (UniversalSerial Bus) interface 118, a video output terminal 124 and a USB socket122.

The light beam incident on the image capture optical system 113 isconverged on the light receiving surface of the CCD module 114. The CCDmodule 114 converts the received optical image into electrical signalsat every 1/30 seconds and transmits the thus generated electric signalsto the controller 111.

The controller 111 includes a CPU module 111 a, a DSP (Digital SignalProcessor) module 111 b, an NTSC encoder 111 c, a flash memory 111 d andan ASIC (Application-Specific Integrated Circuit) including a RAM 111 e.Operation of the digital camera 110 is controlled as the CPU module 111a executes a program stored in the flash memory 111 d.

The image signal output by the CCD module 114 is transmitted to the DSPmodule 111 b. The DSP module 111 b applies predetermined signalprocessing such as digital conversion, gamma compensation and whitebalance adjustment. When a still image is required, the DSP module 111 breads out the image data all the pixels in the effective imaging area ofthe CCD and generates high-resolution digital image data representing animage consisting of 3200×2400 pixels. Otherwise, the DSP module 111 bcontrols the CCD module 114 to obtain a low-resolution image by thinningthe number of pixels or by applying addition to adjoining pixels or thelike to reduce the number of pixels of an image to a VGA size (i.e.,640×480 pixels). The size-reduced (i.e., low-resolution) image data istransmitted to the NTSC encoder 111 c. The data is converted into theNTSC video signal and is transmitted to the video interface 112. Theimage conversion procedure by the DSP module 111 b and the NTSC encoder111 c is executed within less than 1/30 seconds per one image frame.Therefore, the image captured by the image capture optical system 113 isoutput through the video interface 112 as an analog video signal.

The USB cable 102 is connected with the USB interface 118 through a USBsocket 122. The USB interface 118 is connected with a communication I/O117. Further, the communication I/O 117 is connected with the CPU module111 a, which controls the communication I/O 117 and transmits/receivesthe digital data to/from the adapter device 200 through the USB cable102. The adapter device 200 transmits a control signal to the CPU module111 a through the USB cable 102 to control that digital camera 110. Forexample, when a predetermined control signal is transmitted from theadapter device 200 to the digital camera 110, the CPU module 111 a ofthe digital camera 110 captures a high-resolution still image andtransmits the same to the adapter device 200. For another example, whenanother predetermined signal is transmitted from the adapter device 200to the digital camera 110, the CPU module 111 a controls the imagecapture control unit 115 to perform a zooming operation and/or anadjustment of the aperture size.

When the image capture start signal is input to the digital camera 110by the adapter device 200, the CPU module 111 a obtains ahigh-resolution digital image converted by the DSP module 111 b, andencodes the data into a high-resolution image data file in JPEG format,and stores the JEPG file in the storage 116. Further, the CPU module 111a transmits the high-resolution image data file to the adapter device200 through the USB cable 102. For the above operations, the RAM 111 eis used to provide a work area.

FIG. 3 is a block diagram of the adapter device 200. The adapter device200 includes a CPU 201, a USB interface 202, an A/D converter 203, avideo capture 204, a RAM 205, a storage 206, a flash memory 207, anEthernet socket 223 to which the Ethernet cable 302 is connected, anEthernet interface 208, a USB socket 222 to which the USB cable 102 isconnected, and a video input terminal 224 to which the video cable 103is connected.

The USB interface 202 is connected with the CPU 201, which transmits acontrol signal to the digital camera 110 through the USB cable 102connected with the USB socket 222. Further, the CPU 201 obtains thehigh-resolution image data file from the digital camera 110 through theUSB cable 102, and stores the received image data file in the storage206.

The video signal output by the video output terminal 124 of the digitalcamera 110 is received by the A/D converter 203 of the adapter device200 through the video cable 103. The A/D converter 203 digitizes thevideo signal and transmits the digitized video signal to the videocapture 204. The video capture 204 processes the digitized video signaland generates image data representing a low-resolution (i.e., 640×480pixels) image. The above process is performed within a period of 1/30seconds.

The Ethernet interface 208 is connected with the ADSL modem 301. The CPU201 executes an HTTP server program so that other computers connected tothe Internet can download the image data files stored in the storage206.

According to the embodiment, only a predetermined client PC 400 isallowed to access the storage 206. For example, an operator of theclient PC 400 transmits predetermined ID and password to the adapterdevice 200 by operating the input device 403. Then, the adapter device200 performs authentication with reference to the input ID and password.Only to the client PC 400 which is authenticated, the image data filesstored in the storage 206 are transmitted.

The above procedure is performed as the CPU 201 executes correspondingprograms stored in the flash memory 207. Therefore, by rewriting theprograms stored in the flash memory 207, it becomes possible to useanother digital camera, which has the USB interface and the analog videosignal output, to function in the similar way. Accordingly, the systemconfiguration can be changed depending on purposes. It should be notedthat the RAM 205 is used as a work area when the CPU 201 executes suchprograms.

FIG. 4 is a flowchart illustrating an operation of the digital camera110 according to the embodiment.

When the program is initiated, in S101, the CPU module 111 a controlsthe DSP module 111 b so that the signal corresponding to 1 frame ofimage output by the CCD module 114 is converted into the NTSC videosignal, which is output from the video interface 112. Then, controlproceeds to S102.

In S102, the CPU module 111 a checks a status of the communication I/O117 to examine whether the control command has been received from theadapter device 200. If the control commands has been received from theadapter device 200 (S102: YES), control proceeds to S103. If the controlcommand has not been received (S102: NO), control returns to S101.

From S103 to S105, a procedure to be executed is determined inaccordance with an instruction represented by the control commandtransmitted from the adapter device 200.

In S103, it is judged whether the control command indicates a zooming ofthe camera. If the control command indicates the zooming operation(S103: YES), control proceeds to S110. If the control command does notindicate the zooming (S103: NO), control proceeds to S104.

In S104, it is judged whether the control command indicates a capturingof a still image. If the control command indicates the capturing of astill image (S104: YES), control proceeds to S120. If the controlcommand does not indicates the capturing of the still image (S104: NO),control proceeds to S105.

In S105, it is judged whether the control command indicates adjustmentof an aperture size. If the control command indicates the adjustment ofthe aperture size (S105: YES), control proceeds to S130. If the controlcommand does not indicates the adjustment of the aperture size (S105:NO), control returns to S101.

In the flowchart shown in FIG. 4, one of the three procedures describedabove is performed. However, it is an exemplary embodiment, and in anactual configuration, more than three procedures may be included andselection may be made therefrom.

In S110, the CPU module 111 a transmits a zoom command to the imagecapture control unit 115. The image capture control unit 115 controls,upon receipt of the zoom command, the image capture optical system 113to execute zooming operation. Then, control proceeds to S111.

The image capture control unit 115 transmits a predetermined end signalto the CPU module 111 a when the zooming operation is finished. In S111,the CPU module 111 a receives the end signal indicative of thecompletion of the zooming operation and confirms the completion of thezooming operation. Then, control proceeds to S101.

In S120, the CPU module 111 a instructs the DSP module 111 b to capturean image. Then, control goes to S121.

In S121, the DSP module 111 b extracts the output signal of the CCDmodule 114, converts the same to generate image data, and transmits theimage data to the CPU module 111 a. The CPU module 111 a generates animage data file representative of the high-resolution image compressedin JPEG format using the converted image data, and stores the image datafile in the storage 116. Then, control proceeds to S122.

In S122, the CPU module 111 a controls the communication I/O 117 totransmit the image data file stored in the storage 116 to the adapterdevice 200 through the USB cable 102. Then, control proceeds to S101.

In S130, the CPU module 111 a transmits an aperture size adjustmentcommand to the image capture control unit 115. The image capture controlunit 115 controls, upon receipt of the aperture size adjustment command,the image capture optical system 113 to adjust the aperture size. Then,control proceeds to S131.

The image capture control unit 115 transmits a predetermined end signalto the CPU module 111 a when the above-described aperture sizeadjustment operation is terminated. In S131, the CPU module 111 areceives the end signal and recognizes the completion of the aperturesize adjustment and confirms the completion of the aperture sizeadjustment operation. Then, control proceeds to S101.

According to the above-described procedures, the digital camera 110performs capturing of a still image, aperture adjustment, zoomingoperation and the like in accordance with control signal transmittedfrom the adapter device 200.

FIG. 5 is a flowchart illustrating an operation of the adapter device200.

In S201, the adapter device 200 transmits a predetermined signal to thedigital camera 110 through the USB cable 102, and checks a response ofthe digital camera 110 with respect to the transmitted predeterminedsignal. That is, the CPU 201 judges whether the digital camera 110operates correctly based on the response of the digital camera 110.

If it is judged that the digital camera 110 operates correctly (S201:YES), control proceeds to S202. If it is judged that the digital camera110 does not operate correctly (e.g., when the digital camera 110 is notpowered ON) (S201: NO), the procedure shown in FIG. 5 is terminated.

In S202, authentication is performed. That is, control pauses untilpredetermined ID and password are transmitted from the client PC 400.When the predetermined ID and password are transmitted (S202: YES),control proceeds to S203. Until the predetermined ID and password aretransmitted (S202: NO), control repeats S202.

In S203, the CPU 201 judges whether a command is transmitted from theclient PC 400. If the CPU 201 has not received the command from theclient PC 400 (S203: NO), control proceeds to S250. In S250, it isjudged whether a predetermined period (e.g., 30 seconds) has elapsed.That is, by repeating S203 and S250, it is judged whether a status inwhich the CPU 201 does not receive the command from the client PC 400 iskept for the predetermined period.

According to the present embodiment, when the client PC 400 is used forbrowsing the image captured by the digital camera 110 through theadapter device 200, the client PC 400 transmits a request for one frameof moving image at every 1/30 seconds. According to the embodiments, theclient PC 400 receives the thus transmitted still images constitutingthe moving image, which are subsequently reproduced and displayed in theclient PC 400. Therefore, if no signal has been received from the clientPC 400 for the predetermined period, an operator of the client PC 400may operate the client PC 400 so as to stop browsing the images, or theconnection between the client PC 400 and the adapter device 200 may havebeen lost. Therefore, in such a case, i.e., the command has not beentransmitted from the client PC 400 to the adapter device 200 for thepredetermined period (S250: YES), the procedure shown in FIG. 5 isterminated. Otherwise (S250: NO), control returns to S203.

In S204 through S207, a procedure to be executed is determined dependingon an instruction represented by the received command.

In S204, it is judged whether the command indicates “transmission of oneframe of moving image”. If it does (S204: YES), control proceeds toS210. Otherwise (S204: NO), control proceeds to S205.

In S205, it is judged whether the command indicates “capturing of ahigh-resolution still image”. If it does (S205: YES), control proceedsto S220. Otherwise (S205: NO), control proceeds to S206.

In S206, it is judged whether the command indicates the “zoomingoperation”. If it does (S206: YES), control proceeds to S230. Otherwise(S206: NO), control proceeds to S207.

In S207, it is judged whether the command indicates “adjustment of theaperture size”. If it does (S207: YES), control proceeds to S240.Otherwise (S207: NO), control returns to S203.

In S210, the CPU 201 controls the video capture 204 to convert the oneframe of video signal, which is being transmitted from the digitalcamera through the video cable 103, to digital image data representing alow-resolution image. Then, control proceeds to S211.

In S211, the digital image data generated in S210 is compressed tocreate an image data file for animation, which is stored in the storage206. Then, control proceeds to S212.

In S212, the image data file for animation, which is created in S211, istransmitted to the client PC 400. Then, control returns to S203.

Specifically, according to the embodiment, the moving image is realizedby subsequently displaying the low-resolution images, which arerepresented by, but not limited to, JPEG (Joint Photographic ExpertsGroup) files. In S210 and S211, the a frame of the video signal isconverted to a JPEG file. Through the video cable 103, frames, each ofwhich as a VGA (Video Graphic Array) size (i.e., 640×480 pixels), aresubsequently transmitted at a rate of 30 frames/second. Each frame datais converted/compressed into a JEPG file to generate image data files ofanimation, which are subsequently stored in the storage 206. Apredetermined number of thus generated JPEG files are stored, and thenewest file replaces the oldest file in the storage.

When the client PC 400 transmits a request for one frame of the movingimage, the CPU 201 transmits the latest JPEG file when the request isreceived to the client PC 400. As will be described with reference toFIG. 8, the request of the client PC 400 and the transmission of the newJPEG file in response to the request are continuously repeated, therebythe user of the PC 400 can view the moving image.

It should be noted that, depending of the traffic, the file transmissionrate may be less than 30 fps (files per second). However, since thetiming when the adapter 200 receives the request from the client PC 400cannot be scheduled in advance, all the frames (i.e., 30 frames persecond) are stored in the storage 206.

It should be noted that, in the above example, the low-resolution imageis represented by JPEG files of VGA images, and the JPEG files aretransmitted at a rate of 30 fps. However, this configuration may bemodified depending on usage/communication environments. For example, asmaller image (e.g., QVGA: 320×240 pixels) may be used, transmissionrate may be reduced (e.g., 15 fps) and/or a compression rate may beincreased to reduce the amount of data transmitted to the client PC 400.

In S220, the CPU 201 controls the USB interface 202 to transmit anoperation command instructing capturing of a still image to the digitalcamera 110. The digital camera 110 captures a high-resolution stillimage (e.g. 3200×2400 pixels) and transmits an image data filecontaining the high-resolution still image to the adapter device 200(S122 of FIG. 4) when the command transmitted from the USB interface 202is received (S120 of FIG. 4). Thereafter, control proceeds to S221.

In S221, the CPU 201 stores the image data file transmitted from thedigital camera 110 (S122 of FIG. 4) in the storage 206. Then, controlproceeds to S222.

In S222, the image data file stored in the storage 206 in S221 istransmitted to the client PC 400. Then, control proceeds to S203.

In S230, the CPU 201 controls the USB interface 202 to transmit anoperation command instructing the zooming operation to the digitalcamera 110. Upon receipt of the command (S103 of FIG. 4: YES), thedigital camera 110 controls the image capture control unit 115 toperform the zooming operation (S110 of FIG. 4). Then, control returns toS203.

In S240, the CPU 201 controls the USB interface 202 to transmit anoperation command instructing the adjustment of the aperture to thedigital camera 110. Upon receipt of the command (S105 of FIG. 4: YES),the digital camera 110 controls the image capture control unit 115 toadjust the aperture size (S130 of FIG. 4). Then, control returns toS203.

As described above, as the adapter device 200 operates in accordancewith the control signal transmitted from the client PC 400, variousoperations including transmission of moving/still images and control ofthe camera functions.

The above-described and other commands transmitted from the client PC400 to the adapter device 200 are issued as an operator of the client PC400 operates application programs running on the client PC 400.

FIGS. 6 and 7 show examples of screen images on the client PC 400 whenan application program runs.

FIG. 6 shows a main window of the screen when an “image browsing/cameracontrolling program” is executed in the client PC 400. The main windowincludes a low-resolution moving image display area I1, a still imagecapture button B1, a zooming slider S1 and an aperture size slider S2are arranged.

In the moving image display area I1, images transmitted from the adapterdevice 200 (S212 of FIG. 5) are displayed subsequently. Thus, thelow-resolution image is updated at every 1/30 second, thereby a movingimage displayed on the moving image display area I1.

If the operator of the client PC 400 operates the input device 403 toclick the button B1, the command instructing the “capture of thehigh-resolution still image” is transmitted from the client PC 400 tothe adapter device 200. The zoom slider S1 and the aperture size sliderS2 indicate current status of zooming condition and the aperture size,respectively. Further, if the operator of the client PC 400 operates theinput device 403 to move the zoom slider S1 and the aperture size sliderS2, the commands instructing the “zooming operation” and the “adjustmentof the aperture size” are transmitted from the client PC 400 to theadapter device 200, respectively.

Specifically, if the operator clicks the button B1, a still imagedisplay window as shown in FIG. 7 is displayed on the monitor 402. Inthe still image display window, a still image display area I2 isarranged. The image of the image file transmitted from the adapterdevice 200 (S222 of FIG. 5) is displayed in the still image display areaI2.

Thus, in a typical case, the operator observes the moving imagedisplayed on the moving image display area I1, and adjust the zoomingcondition and the brightness (i.e., the aperture size). Then, when theoperator clicks the button B1, a high-resolution image corresponding tothe image displayed in the moving image display area I1 is captured andtransmitted from the digital camera 110 via the adapter device 200.

FIG. 8 shows a flowchart illustrating the procedure of the imagebrowsing/camera controlling program executed in the client PC 400. InS301, the client PC 400 accesses the adapter device 200 through theInternet, and transmits the predetermined ID and password assigned tothe client PC 400 to the adapter device 200.

In S302, it is judged whether the client PC 400 is connected to theadapter device 200 and is successfully authenticated (cf. S202 of FIG.5: YES). If a code indicating “successfully authenticated” is receivedfrom the adapter device 200 (S302: YES), control proceeds to S303. Ifthe adapter device 200 does not respond for a predetermined period(e.g., 30 seconds) as the adapter device 200 has not operated, hasfailed to authenticate or the like, control proceeds to S340.

In S340, a message indicating the operator that the connection is notestablished is displayed, and the operator is asked to re-execute theprocedure for establishing the connection with the adapter device 200.Then, the operator operates the input device 403 to input theinstruction indicating to re-execute or terminate the procedure.

If the operator instructs the re-execution (S340: NO), control returnsto S301. If the operator instructs to terminate the procedure (S340:YES), the procedure shown in FIG. 8 is terminated.

In S303, the client PC 400 transmits a command requesting fortransmission of a frame of moving image to the adapter device 200. Then,control proceeds to S304. Upon receipt of this command (S204 of FIG. 5:YES), the adapter device 200 transmits the image data representing aframe of moving image to the client PC 400 (S212 of FIG. 5).

In S304, the client PC 400 displays the image data, which has beentransmitted from the adapter device 200 in S212 of FIG. 5, in the movingimage display area I1 (see FIG. 6). Then, control proceeds to S305.

In S305, it is judged whether a command is input by the operator of theclient PC 400. If the command is input (S305: YES), control proceeds toS306. If the command is not input (S305: NO), control proceeds to S309.

In S306 through S308, a procedure to be performed is determineddepending on the command input by the operator.

In S306, it is judged whether the input command indicates the “zooming”.If the input command indicates the “zooming” operation (S306: YES),control proceeds to S310. If the command is not the “zooming” command(S306: NO), control proceeds to S307.

In S307, it is judged whether the input command indicates the “capturingof high-resolution still image”. If the input command indicates thecapturing of the image (S307: YES), control proceeds to S320. Otherwise(S307: NO), control proceeds to S308.

In S308, it is judged whether the input command indicates the“adjustment of the aperture size”. If the input command indicates theadjustment of the aperture size (S308: YES), control proceeds to S330.If not (S308: NO), control proceeds to S309.

In S310, the client PC 400 transmits a command instructing the zoomingoperation to the adapter device 200 through the Internet. Upon receiptof the command (S206 of FIG. 5: YES), the adapter device 200 transmits acommand instructing the zooming operation to the digital camera 110(S230 of FIG. 5). Then, control proceeds to S309.

In S320, the client PC 400 transmits a command instructing to capture astill image to the adapter device 200 through the Internet. Then, uponreceipt of this command (S205 of FIG. 5: YES), the adapter device 200transmits the high-resolution image data file to the client PC 400 (S222of FIG. 5). Then, control proceeds to S321.

In S321, the still image display window (FIG. 7) is opened, and theimage represented by the image data file transmitted from the adapterdevice 200 is displayed in the still image display area I2. Thereafter,control proceeds to S309.

In S330, the client PC 400 transmits a command instructing to adjust theaperture size to the adapter device 200 through the Internet. Then, uponreceipt of this command (S207 of FIG. 5: YES), the adapter device 200transmits a command to perform the adjustment of the aperture size tothe client PC 400 (S240 of FIG. 5). Then, control proceeds to S309.

With the above configuration, the operator of the client PC 400 canmonitor the moving image simultaneously with the capturing thereof, andobtain the high-resolution still image at a desired timing.

In the above-described embodiment, the digital camera 110 and theadapter device 200 are connected using the video cable 103 and the USBcable 102 so that the digital camera 110 and the adapter device 200 canbe arranged freely. However, the invention is not limited to thisconfiguration, and the adapter device may be detachably coupled with thedigital camera without using the cables. Such a configuration will bedescribed hereinafter as a second embodiment.

FIG. 9 is a perspective view of a digital camera 1100 and an adapterdevice 2000 according to a second embodiment.

On a side wall 1100 a of the digital camera 1100, a video output socket1240, a USB socket 1220, guide holes 1250 and lock claw inserting holes1260 are formed. On a side wall 2000 a of the adapter device 2000,facing the side wall 1100 a of the digital camera 1100, guide pins 2250,locking claws 2260, a video input plug 2240 and a USB plug 2220 areprovided. The locking claws 2260 are L-shaped hooking members, which areformed on a single plate member (not shown) accommodated in a body ofthe adapter device 2000. The single plate member is slidable in alongitudinal direction of the side wall 2000 a and biased with a spring(not shown) such that, when adapter device 2000 is coupled to thedigital camera 1100, the locking claws are inserted through the lockingclaw insertion holes 1260 and engaged with the side wall 1100 a. Theadapter device 2000 is further provided with a lock release button 2270on the top surface thereof.

It should be noted that the USB socket 1220, the video output socket1240, the USP plug 2220, the Ethernet interface socket 2230, the videoinput plug 2240 correspond to the USB socket 122, the video outputterminal 124, the USB socket 222, the Ethernet socket 223 and the videoinput terminal 224 of the network camera system 1 according to the firstembodiment.

When the lock release button 2270 is depressed, the locking claws 2260are moved in a direction opposite to the biased direction so that theengagement of the locking claws 2260 with the side wall 1100 a isreleased.

The guide pins 2250 are protruded from the side wall 2000 a. The guidepins 2250 are received by the guide holes 1250 formed on the side wall1100 a of the digital camera 1100, thereby the positional relationshipbetween the digital camera 1100 and the adapter device 2000 isrestricted. On a side wall 2000 b, which is opposite to the side wall2000 a of the adapter device 2000, an Ethernet interface socket 2230 isprovided.

When the adapter device 2000 is coupled to the digital camera 1100, theguide pins 2250 are inserted in the guide holes 1250. Then, the lockingclaws 2260, video input plug 2240, USB plug 2220 face the locking clawinsertion holes 1260, video output socket 1240 and the USB socket 1220,respectively. As the locking claws 2260 engage with the side wall 1100 aas described above, the terminals are electrically connected, and theadapter device 2000 are firmly coupled to the digital camera 1100. Asdescribed above, by depressing the lock release button 2270, the adapterdevice 2000 can easily be detached from the digital camera 1100.

As described above, by depressing the lock release button 2270, theengagement of the locking claws 2260 with the insertion holes 1260 isreleased, and the adapter device 2000 can be detached from the digitalcamera 1100.

According to the configuration of the second embodiment, the adapterdevice 2000 can be coupled to and detached from the digital camera 1100easily. Further, since no cables are required when the adapter device2000 is coupled to the digital camera 1100, the entire system can bemade compact.

As described above, according to the invention, the functions of thedigital camera can be used efficiently. Regarding the monitor image(moving image), for which the response is important, the image generatedby the digital camera is efficiently used. Regarding the functionsrequiring interactivity with respect to the camera, such as operationcontrol or transmission of high-resolution images, by making use of theUSB interface, which is provided in the digital camera, transmission ofcontrol commands and/or high-resolution image data can be executed.

Accordingly, the adapter device is only required to have additionalfunctions which are not provided in the digital camera and are necessaryto configure the network camera system described above. Since commercialdigital camera may be provided with the functions described above, aninexpensive network camera system can be configured relatively easily.

1. A network camera system including at least one client, a digitalcamera and an adapter, said client and said adapter being connected witheach other through a network, said camera comprising: an image capturer;an analog video signal outputter that outputs an analog video signalrepresenting a moving image captured by said image capturer; a digitalimage signal outputter that outputs a digital image signal representinga still image captured by said image capturer; a control commandreceiver; and an operation controller that controls an operation of saidcamera in accordance with the control command received through saidcontrol command receiver; said adapter comprising: a file server thatreceives the digital image signal from said camera and stores an imagefile representing the still image captured by said image capturer, saidfile server allowing said at least one client to download the image filefrom said file server through the network; a streaming server thatreceives the analog video signal from said camera and creates streamingdata corresponding to the received video signal, the streaming databeing transmitted to said client through the network; an adapter commandreceiver that receives an operation command from said client through thenetwork; and an adapter command transmitter that transmits a controlcommand corresponding to the operation command to said camera, and saidclient comprising: a browser that downloads the image file from saidfile server and displays an image represented by the image file, saidbrowser being capable of processing the streaming data and displayingthe moving image represented by said streaming data; and a clientcommand transmitter that allows an operator to input an operationcommand indicative of an operation to be executed by said camera andtransmits the operation command to said adapter through the network. 2.The network camera system according to claim 1, wherein the operation tobe executed by said camera includes capturing a still image when theoperation command is input to said client command transmitter by theoperator.
 3. The network camera system according to claim 1, wherein thedigital image signal representing the captured image output by saiddigital image signal outputter is received by said file server andstored in said adapter.
 4. The network camera system according to claim1, wherein the operation to be executed by said camera includes at leastone of zooming operation of said camera, capturing a still image andadjustment of brightness of an image captured by said camera.
 5. Thenetwork camera system according to claim 1, wherein a resolution of thestill image is greater than that of the moving image.